
//  二级导航

var timeout         = 500;
var closetimer		= 0;
var ddmenuitem      = 0;
// open hidden layer
function mopen(id)
{	
	// cancel close timer
	mcancelclosetime();
	// close old layer
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
	// get new layer and show it
	ddmenuitem = document.getElementById(id);
	ddmenuitem.style.visibility = 'visible';
}
// close showed layer
function mclose()
{
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
}
// go close timer
function mclosetime()
{
	closetimer = window.setTimeout(mclose, timeout);
}
// cancel close timer
function mcancelclosetime()
{
	if(closetimer)
	{
		window.clearTimeout(closetimer);
		closetimer = null;
	}
}
// close layer when click-out
document.onclick = mclose; 
 

 
